Summer knights

Q:Imagine knights of old gathering for a roundtable discussion with modern baseball players. What "materials strength" tips could they share? ­C. Ripkin

A: White ash was celebrated in medieval times as the only proper wood from which to construct the lances of knights errant, says Robert K. Adair in The Physics of Baseball. "An ash lance was light enough to carry and wield and strong enough to impale the opposition."

Pounding the opposition is the aim of today's baseball sluggers, whose white ash bats swung at 70 mph will endure the 8,000-pound force imparted to a well-hit ball, as you should know, C. A bat made instead of green ash or black walnut will come close to the same "feel" and hitting characteristics but lack in hardness and strength.

Q:What's the oldest known living thing on Earth? ­G. Moses

A: A bristlecone pine tree in the White Mountains of eastern California was cut down in 1963, at 4,844 years old, says University of Tennessee geographer Henri D. Grissino-Mayer. Currently, another bristlecone pine named "Methuselah" is 4,800 and counting. Foxtail pines, also in California, can live to about 3,600, giant sequoias 3,000.

Marking tree-time are "rings" of darker wood concentrically through the trunk, one per annum in some latitudes, precisely countable by dendrochronologists and revelatory of the Earth's past.

For instance, wetter years may trigger more wood and wider rings. Also readable in the rings, both ancient and modern, says Grissino-Mayer, are trends of air pollution, water pollution, acid rain, drought, volcanic actions, glacial movements, earthquakes, landslides, forest fires, insect outbreaks, even past tsunami.

"A tree is literally a long-term weather station. Standing sometimes for thousands of years, it is the ultimate recorder of Earth's environmental past, holding clues for us to a wiser future."

Q:Take a rope and tie it from one goal post to the other on a standard football field, tight along the ground. The rope will be 120 yards (360 feet) long. Now add one foot to the length of the rope, and pull up the slack at the 50-yard line. What can pass under the rope teepee at its peak? a) a mouse, b) a rabbit, c) a dog, or d) an elephant? ­H. Houdini

A: To figure this, use the Pythagorean Theorem, 2,500 years old and well known to geometry kids everywhere, says California Polytechnic State University mathematician Laurie Riggs. If the hypotenuse C of a right triangle is 180.5 feet (half the rope's 361 ft.) and the triangle "leg" A along the ground is 180 ft., the peak height B (the other "leg") will solve the equation: A squared + B squared = C squared. Plugging in the numbers, 32,400 + B squared = 32,580. Then B squared = 180, so B = 180's square root, or 13.4 ft. Therefore, pick d), a pachyderm could pass, no problem.

A: The latter will "do in" a rider sooner because the lack of headwind breeze makes it tougher to cool the body, says Oxford physiologist Frances Ashcroft in Life at the Extremes: The Science of Survival. This has startled competition cyclists brought into a test lab, who petered out rapidly despite enduring grueling 12-hour uphill stretches in races. Turn a fan on the static bikers and they last much longer.

This phenomenon may be behind the occasional instances of heatstroke when a cyclist or runner finishes exercising abruptly, as well as the horseman's old maxim to be sure to cool a horse down after a hard workout.